Detergent compositions comprising benzimidazolylstilbene whitening and brightening agents



a v I 2,931,148 j DETERGENT COMPOSITIONS COMPRISINBENZIMIDAZOLYLSTILBENE WHITEN- ING AND BRIGHTENING, AGENTS Nathan N.Crounse, Cincinnati, Ohio, assignor to Sterling Drug Inc.,:New York,N.Y., a corporation of 'Dela'- ware No Drawing. Original applicationApril 21, 1955, Serial No. 503,015, now Patent No. 2,838,504, datedvJune 10, 1958. Divided and this application December 2, 1957, Serial No.703,725

8 Claims. (Cl. 252-117) This invention relates to novel detergentcompositions comprising certain fluorescent compounds of the,benzimidazolylstilbene series useful as whitening and brighteningagents.

The present application is a division of my co-pending applicationSerial No, 503,015, filed 'April 21, 1955 (now colored fabrics,especially in the optical bleaching of white fabrics, since they aresubstantive. even inlow concennations to a wide variety of natural andsynthetic fibers, they impart a desirable blue-white hueto the whitefibers and brighten colored fibers treated therewith, and they haverelatively high light stability Moreover, my prior 'inventionprovidesfor the first timerfluorescent' whitening and brightening agents of the'stilbene series having the foregoing properties andalso havingsatisfactory stabilityto chlorine-containing commercial laundrybleaching agents such as sodiumhypochlorite and calcium hypochlorite.

The whitening and brightening agentsuseful in preparing the detergentcompositions of this invention are stilbenes bearing in both the 4- and4'-positions benzimidazol-Z-yl radicals which are the same. or.different and they have the structural Formula '1 shown below,

Formula I where R, R R and R are radicals of. the class consisting of:hydrogen; lower alkyl containing 1-4 carbon atoms;

7 low concentrations in aqueous dispersions.

2,937,148 Patented May 17, 1960 droxypropyl; ,2-hydroxy-3-sulfopropyl;,hydroxy-oxaalkyl 10 containing 3 -15 carbon atoms, for example2-hydroxy-3- (Q2,3-dihydroxypropoxy) propyl,2-hydroxy-3-(2-hydroxyethoxy) propyl, and 2-hydroxy-3[-(Z-hydroxyethoxy) -eth-. oxy] propyl; carboxy-lower alkyl containing-2-6 carbon atoms, for example carboxymethyl and Z-carboxyethyl;

cyano-lower alkyl containing 3-6 carbon atoms, for ex ample Z-cyanoethyland 3-cyanopropyl; monocyclicaralkyl containing 7-11 carbon atomsforexample benzyl and benzyl containing 1'-3 substituents, which can bethe same I or difierent, in the benzene ring, as halobenzyl, such asortho c hlorobenzyl, para-fiuorobenzyl, 2,4-dichlorobenzyl,

and meta-bromobenzyl, lower alkylbenzyl such as ortho-.

methylbenzyl and para-isopropylbenzyl, and loweralkoxybenzyl such asp-methoxybenzyl and 3,4-diethoxybenzyl, as well as2-chloro-4-methoxybenzyl, 3-methoxy-4-methyl benzyl,2-methoxy-4-chlorobenzyl, and the like; and allyl and methallyl. I

In general, the compounds of the above structure are high-melting yellowor green-yellow solids which have the following solubilitycharacteristics. They are insoluble in water, hydrocarbons, halogenatedhydrocarbons, ketones, ethers and mineral acids. They are moderatelysoluble in N,N -dimethylformam ide and dimethyl sulfoxide;;some ofthem-aresoluble in acetic acid; and'the compounds wherein atleast one ofY and Y is hydrogen are weakly acidic and soluble in alcoholic alkali toyield yellow to red solutions. Thecom-pounds wherein Y and Y containtwo. or rnore'hydroxyl groups have some solubility in glacial aceticacid, this solubility being highest in the dialkylated compounds whereinboth Y and Y contain two or more hydroxyl groups in each radical. TheN,N-dialkylated compounds are slightly soluble in lower alkanols such asethanol, but this solubility is not increased by addition of alkali. r

When the above-described compounds are dispersed in aqueous media, theyfiuoresce'blue-white under ultraviolet light and show a wide range ofabsorption in the ultraviolet region. These compounds are substantive toa wide variety of natural and synthetic fibers, for example, cotton,cellulose acetate, viscose "rayon, nylon, silk, and Orlon, and areabsorbed by such fibers even from very The compounds have relativelyhighstability to sunlight, soap, synthetic detergents and chlorinecontaining bleaching agents.

The above-described properties of these benzimidazolylstilbenes makethem especially valuable as whitening and brightening agents in treatingwhite and colored fabrics to neutralize the yellowness inwhite textilesor to enhance the brilliance fofi colored textiles. In such utilizationthe relatively high resistance of my compounds to chlorine bleachingaudio light are distinct and surprising advantages, since the'previouslyknown whitening and brightening' agents of .the stilbene series have hadas their chief drawbacks a lack of resistance to chlorine-containingbleaching agents and ease of decomposition under infiuence of light. i

A further important advantage of the preferred species of thesebenzimidazolylstilbeneslies in the fact that on repeated applications towhite fabrics, thereby building up the amount of the whitening agent onthe fibers, the fabrics remain bluish-whitean'd'do not develop anundesirable discoloration, for example a red or gray color, such as isproduced by many of the known optical bleaching agents when they areapplied repeatedly, as for instance in successive launderings.

Although the benzimidazolylstilbenes used in my invention aresubstantially insoluble in water, they are readily utilizable asdispersions in aqueous media. Thus, the treatment of textile fabricswith these compounds is readil'y carried out by'conventional procedures.For example, an aqueous dispersion containing about 0.0001 to 0.5% byweight of the compound and one .or more suitable dis! persing agents,for instance soap or an organic sulfonate or sulfate, is applied to thefabric, which absorbs the fluorescent'compound and is whitened orbrightened beneficially thereby. This application of the compound can beconveniently carried out in conjunction with a rinsing or washingoperation.

The dispersions are readily formed, for-example, by dissolving thecompound in a suitable solvent such as N,N-

a dimethylformamide, alkaline'aqueous alcohol, or glacial acetic acidand mixing the solution thus obtained in desired quantity with anaqueous soap or detergent solution. The compounds of Formula I whichbear no substituents in the benzene rings of the benzimidazol-Z-ylradicals are much more readily dispersed in this manner than are thecorresponding highly substituted compounds, and it is for this reasonthat the sum of the carbon atoms in R R R and R in each ring, should belimited to about 16 carbon atoms. When a high degree of dispersibilityis a desired feature in the utilization of my compounds, I generallyprefer to employ those in which at least two of the radicals R R R and Rare hydrogen and the sum of the carbon atoms in all four substituents,in each ring, is no more than two. 7

A preferred mode of using and marketing the compounds is byincorporating them into solid or liquid soaps and detergents in anappropriate concentration, for ex-. ample 0.02 to 0.5% of the whitening'andfbrightening agent by weight. The resulting compositions are thesubject of the instant invention.

For incorporation into white detergents, I particularly prefer thesymmetrical and unsymmetrical N,N'-bis(oxyalkylated) compounds havingthe structural formula V Formula IV wherein Y? and Y are the sameordifierent and are members of the group consisting of hydrogen,hydroxy-lower alkyl radicals containing 2-6 carbon atoms, andhydroxyoxaalkyl radicals containing 3-15 carbon atoms, at least one of Yand Y being other than hydrogen. These preferred species have been foundboth as individual species and in admixture with each other to haveespecially high stability in the presence of detergents and to haveexceptionally good dispersibility in commercial detergents comprisingorganic sulfates or sulfonates, for example sodium lorol sulfate andsodium (higher alkyl) benzenesulfonates,

and. various builders such as sodium triphosphate (also known, as sod umtripolyphosphate) and sodium sultatc. in

addition to possessing the other advantageous properties common to allof my new compounds as set forth hereinabove. pounds (FormulaIV) towhite fabrics of natural and synthetic fibers does not cause developmentof an undesirable color.

The benzinlidazolylstilbenes can be prepared by employing as startingmaterials appropriately ortho-substituted bisanilides of4,4-stilbenedicarboxylic acid. In general, I have found that itis mostconvenient to prepare the compounds wherein Y and Y in the gener lFormula I are both hydrogen (FormulaII'I below) by'cyclization of abis-(ortho-aminoanilide) of a 4,4'-stilbenedicarhoxylic acid by heatingit under acidic conditions; the reaction proceeds in accordance with thefollowing equation.

I H Formula 111 Usually,l prefer to prepare the bis-(ortho-aminoanilide)starting materials (Formula II) for the above process by reduction ofthe corresponding bis-(ortho-nitroanilides). When this is done, it isfrequently advantageous to reduce the bis-(ortho-nitroanilide) and thencyclize the resulting bis-(ortho-aminoanilide) directly withoutisolating it. Thus, the reduction and cyclization reactions areconveniently effected in a single operation by reducing the 4,4stilbenedi [carbox(ortho-ni tronanilide)] with a mixture of an acid, forexample hydrochloric acid or acetic acid, and a metal such as aluminum,iron or zinc and then, if necessary, heating the reaction mixture toefiect cyclization to form the desired4,4'-bis(bcnzimidazol-2-yl)stilbene (Formula III). A mixture of stannouschloride and hydrochloric acid can also be employed as the reducingmedium in this method- When an-organic acid is employed in the reducingmedium, it is frequently advantageous and sometimes necessary to addhydrochloric acid or similar strong inorganic acid to complete thecyclization step. Sodium hydrosulfit'e can be used as the reducing agentbut, when this is done,"for best yields the bis-(orthoarninoanilide)should be isolated prior to the cyclization Moreover, repeatedapplication of these com- The bis(ortho-nitroanilides) which have thestructural formula l are readily obtained by heating and stirring onemole of 4,4'-stilbenedicarbo'nyl chloride with approximately two molesof the appropriate ortho-nitroaniline, preferably in a solvent, forexample chlorobenzene, and in the presence of an acid-accepting medium,for example an N,N-dialkylaniline.

The cyclization is generally carried out by heating thebis(ortho-aminoanilide) (Formula :II) for one to six hours at 80-l50 C.,a range of 100120 C. being usually preferred. For best results, asolvent should be employed in carryu'ng out the reaction and for thispurpose Z-methoxyethanol, 2-ethoxyethanol, and 75-90% acetic acid havebeen found to be especially useful.

Using the'abo've process, for example the following compoundsof FormulaHI are obtained by reducing the indicated bis(orth-nitroanilides) of4,4'-stilbenecarboxylic acid and cyclizing the correspondingintermediate bis(ortho-aminoanilide) thereby-produced in each instance(as will be appreciated, the tautomerism of 'these products'afiords inmany cases alternative choices '4,4'-bis[4,5,7(or'4,6,7)-trimethoxybenzimidazol-2-yl]- stilbene, from thebis(3,5,6-trimethoxy-2-nitroanilide);

- 4,4 bis[4(or 7) methylbenzimidazol 2-yllstilbene,

from the bis(3-methyl-2 nitroanilide);

- 4,4 bis[5 (or 6)-tert-butylbenzimidazol2-yl]stilbene,

from the bis(5-tert-butyl-2-nitroanilide);

4,4'-bis(5,6-dimethylbenzimidazol-2 yl) stilbene, from thebis(4,5-dimethyl-2-nitroanilide);

' 4,4 bis(4,5,6,7 tetramethylbenzimidazol 2 yl)stilbene, from thebis(3,4,5,6-tetramethyl-3-nitroanilide);

4,4'-bis [5(or 6)-ethylbenzimidazol-2-yllstilbene, from thebis(4-ethyl-2 -nitroanilide);

4,4'-bis [5(or 6) chlorobenzimidazol-2-yl]stilbene,

from the bis(4-chloro-2-nitroanilide);

4,4 bis[5(or 6) -'fluoro(benzimidazol 2-yllstilb ene,

{from the bis(5-fluoro -2-nitroanilide);

4,4 bis [4,6(or 5,7) dibromo(ben ziinidazol-2-yl]stilbene, from thebis(3,5-dibromo-2-nitroanilide);

4,4 bis[4,5,'6(or 5,6,7)-tricliloro(benzimidazol 2-yl]- stilbene, fromthe bis(4,5,6 trichloro-2-nitroanilide);

-4,4'-bis [6 methoxy 5'-fluoro(or 5-methoxy-6-fluoro)-benzimidazol-Z-yllstilbene, from the bis(4-methoxy-5-fluom-Z-nitroanilide);

4,4'-bis'[4-bromo-6,7-methylenedioxy(or 7 homo-4,5-methylenedioxy)benzimidazol-2-yllstilbene, from the bi:-(3-bromo-5,G-methylenedioxy-Z-nitroanilide); and

4,4'-bis[5-methoxy-6-methyl(5-methyl-6 methoxy)-benzimidazol-Z-yllstilbene, from the bis(4-methoxy-$-methyl-Z-nitroanilide). v The N,N'-unsubstituted compounds (Formula III)obtained in the manner described above are useful per se as Whiteningand brightening agents. They react readily with alkylating agents toyield N-monoand symmetrical or unsymmetrical N,N-di-(alkyl orsubstituted alkyl) derivatives, so that they are also'useful as startingmaterials'for the convenient preparation of the whitening andbrightening agents of Formula I wherein one or both of Y 'andY are alkylor substituted alkyl radicals of the type hereinbefore defined. Thealkylation reaction is readily carried out by heating'a4,4'-bis(benzimidazol-2- yl)'stilbene (Formula III) with the appropriatealkylating agent. Usually a heating period of about one to four hours at50-125? C.'is sufiicient to produce a satisfactory yield of the desiredproduct. The'alkylating agents .useful in this conversion include forexample esters of strong organic and inorganic acids having the formulaZ-An, where Z is a member of the class consisting of lower alkylcontaining 1-6 carbon atoms, hydroxy-lower alkyl containing 2-6 "carbonatoms, 2-hydroxy-3-sulfopropyl, hydroxy-oxaalkyl-containing 3-15 carbonatoms, carboxylower alkyl containing 2-6 carbon atoms, cyano-lower alkylcontaining 3-6' carbon atoms, and monocyclic aralkylcontaining 74 1carbon atoms and An is the anion of a strong acid. Illustrative of theseesters are: methyl sulfate, ethyl sulfate; methyl. ptoluenesulfonate;lower alkyl halides, such as methyl chloride, ethyl bromide, butylchloride, and hexyl chloride; monocyclic aralkyl halides, such as benzylchloride, p-methoxybenzyl chloride, o-chlorobenzyl chloride,2-chloro-4-rnethoxybenzyl bromide, and benzyl bromide; allyl andmethallyl halides, such as allyl chloride and methallyl bromide;carboxylower alkyl halides, such as Z-carboxyethyl chloride andcarboxymethyl bromide; cyano-lower alkyl halides, such as 2-cyanoethylchloride; hydroxy-lower alkyl halides, such as 2,3-dihydroxypropylchloride (or glycerol alpha chlorohydrin),1ethylene chlorohydrin,ethylene bromohydrin, isobutylene chlorohydrin; Z-hydroxy-B-sulfo;propyl chloride or bromide; hydroxy-oxaalkyl halides, such as2-hydroxy-3-(2-hydroxyethoxy)propyl chloride,Z-hydroxy-B-(2,3-dihydroxypropoxy)propyl chloride and2-hydroxy-3-[2-hydroxyethoxy)ethoxyJ-propyl chloride.

Also useful as alkylating agents are 1,2-lower alkylene oxidescontaining 2-6 carbon atoms, for example, ethylene oxide, propyleneoxide, glycidol, and epichlorohydrin; and acrylonitrile andmethacrylonitrile.

The N monoalkylated compounds (Formula I, where only one of Y and Y ishydrogen) are obtained by heating preferably one or advantageouslyslightly more than one molecular equivalent of the appropriate alkylating agent with one molecular equivalent of the 4,4'-bis-(benzimidazol-2-yl)stilbene (Formula 1H). Minor proportions of thecorresponding N,N'-dialkylated compound (Formula I, where neither of Yand Y is hydrogen) and of unreacted N,N'-unsubstituted starting material(Formula III), varying in amounts depending in part on therelativeproportions of the reactants and in part on the reactionconditions, will be found associated with the N-monoalkylated compoundobtained as the chief product of the alkylation reaction. If desired,the N-monoalkylated product can be purified, for example by use ofsuitable solvents, but ordinarily it is unnecessary and uneconomical forpractical purposes to eifect such purification since the mixture is,directly useful as a whitening'and brightening agent.

."Asiwill be understood, the use of larger proportions of the alkylatingagent favors higher yields of the N,N- dialkylated compound. When thisis the desired product, there a'reofcourse required by theory atleasttwo moleculargequivalentspf the'alkylatingagent per: equivalent of the4,4 -bis (benzimidazol-Z-yl) stilbene (Formula III) as a matter offactforbestconversion to the dialkylated product; ;an excess ipf';the*alkylating .agent should be employedgfor exa'rnplean excess of 1-4equivalents of the" alkylating agent. The N,N-dialkylated compoundsobtainediin. this manner are symmetrical. When an unsymmetrical: productis desired, an N-rnonoalkylated compound or, alternatively; a reactionmixture containing it is treated-with.- a different" alky-lating agent,therebyproducing a' compound "of Formula I whereinIY and Y areditterent. alkyl or substituted alkyl radicals.

When the alkylating agent has a hydroxyl' group in its structure; forexample a hydroxy-lower alkyl or hydroxyoxaalkyl compound, the hydroxylfunction. in the result ing N-monoalkylated product (e.g., Formula I, Y=H, Y hydroxy-lower alkylror hydroxy-oxaalkyl) interacts with a secondequivalent of the same or a different alkylating. agent to yieldpreferentially O-alkylated products. rather than the expectedN,N-dialkylated derivative, the latter being produced only in relativelysmall amount. The use of a large excess of the alkylating agent leads tosubstantially complete production of N,N-disubstituted products.

- Instead of using the alkylation process described above, analternativemethod for obtaining N-(Z-cyano-lower alkyl)- and N,N'-di(2-cyano-loweralkyl)- compounds of Formula I is' by interacting an acrylonitrile withthe N,N.-unsubstituted starting material (Formula III). The

hydrolysis of these mono.- and di-Z-cyanO-lower. alkyl compounds to thecorresponding Z-carboxy-lower alkyl compounds affords an alternativeroute to the latter substances;

-'For the preparation of the N,N-dialkyland N,N- di(m'on'ocyclicaralkyl) compoundsof Formula I, there can be employed instead of thealkylation process an alternative method which comprises cyclizing a4,4: stilbenedi{carbox[ortho (mono lower alkylamino or mono-monocyclicaralltylrminofl-anilide} by heating it' in the presence of aninorganicacid, 'forexample hydrochlorieacid; and preferably in a solvent such as2- rnetho'xyethanol 'or 2-ethoxyethanol; The reaction conditions forthis cycl-i'zationare substantially the same as for the cycliz'ation ofthe corresponding ortho-primary amino compoundsdes'c'ribed hereinabove.

' My invention'i's illustrated by the following examples without,however, being limited thereto.

, EXAMPLE 1 4,4'-bis( bnzimidizZoZ-Z-yl) stilbene 2A. A solution of: 290g. (2.1 moles) of ortho-nitroaniline in 2860-g. of N.N'-dimethylanilinewas placed in a. ten-liter, three-neck flask fitted with a high-speedagitator and thermometer and was heated to 50-55 C. To this solutionthere was then added during a period of three to four minutes a heated(129-432" C.) solution of 305 g. (1 mole) of 4,4'-stilbenedicarbonylchloride in 315.80g. otchlorobenzene. The last remnants of the acidchloride were rinsed from itsv container-into the reaction flask withabout 100 g. of boiling chlorobenzene. The temperature of the resultingreaction mixture rose to about -90 C. and after a few minutes yellowcrystals began to separate from solution and the reaction mixturethickened. The reaction mixture was held at -90 C. for one houriandwasthen-stirred at -105 C. for eight hours. The reaction mixturewas-cooled to 25 C. and filtered. The solid cake thus collected waswashed successively with 255 g. of chlorobenzene, 475 g. of methanol,and finally with water until a sample of wash liquor was colorless. Theyellow product was oven-dried at 80400 C. There was thus obtained 430 g.of 4,4- stilbenedi[carbox(ortho-nitroanilide)1 having the structuralformula which melted at:305307 C. 3 l

Analysis.-C alculated for C H O N C. 66.00%; H, 3.94%; N,'ll'.01%; O,18.85%. Found: C, 65.85%; H; 4.19 N,-l0.61%; 0,1930% (direct analysis).

In the preparation of the above dianilide, it was-found that thechlorobenzene could be replaced withorthodichlorobenaene andatheN,N;dimethylanilinecould be replaced with N,N-diethylaniline to affordthe same prod not in satisfactory yield. The product was also obtained,but inpoorer yield and quantity by condensing the reactants ina'solventmediumof refluxing chlorobenzene while permitting the hydrogen chlorideformed in-the re'action'to distill oil. f

B. To a two-liter, three-necked flask fitted withahighspeed stirrer;reflux condenser,- dropping funnel,; and thermometer there were added45- g. (0.0885 mole) of 4,4-stilhefnedi-Ecarbox?(ortho nitroanilide)]and- 1125 ml. of 2-methoxyethanol The mixture was heated to refluxtemperaturetabout C.) and then. the-outside source of heat was removed.Through the-dropping funnel there was added to the; mixture; a solutionof 1293:;- "(0.575 mole) of stannous chloride dihydrate in 2552 of con'centrated-hy'drochloric acid. (about 38% hy weight)v at such a rate thatrefluxing was quite'rapid butwfill the; capacity of, thej'condenser toprevent loss of solvent; the, time required for the-addition wasaboutseven minutes."-D.uri'ng the'additionthe temperature .of themixture dropped to about 107 After the addition of the'reducing agentwas completed, the reaction mixture was refluxed -for;our'hours and thenwaseooled overnight in a refrigerator. .The solid which had separatedfrom solution was collected on a filter, andthejfilter-cake waswashejdrf'ree of acid with Water as-determined by test ing: with' Congored. 7 The bright yellow powder -thus obtained, which was 14,4-bis.benzimidazo lw2yl) stilbene dihydrochloride, weighed 41' g.This" product. wassus pended i'n 4'l.0jml; of 95% ethanol and 57 g;of50% aqueous sodium hydroxide solution was added. The mixture was;refluxed until substantially-all' ot' the solid had dissolved and wasthen-filtered tojremove' a; small amount of insoluble material. .Thefiltrate was .diluted with about four liters of water and filtered tocollect. the solid 'whichseparated from solution. -The-collected solidwas washed free=0f alkali with waterv and dried at l00- under reducedpressure. There. was thus obtained .33 g. of 4,4-bis(benZimida7.ol2-yl)stilbene as a pale yellow solid which did not inelt when heated to-Analysis.--Calculated for CHN: 'C, 81.54%; H, 4.88%; N, 13.58%. Found:C,'8l.03%; H,5.10%; N, 13.36%.

The free 'base was also obtained by dissolving the dihydrochloride inalkaline 2-rnethoxyethanol, diluting the solution with water, filteringto collect'the solid which separated from solution,and washing theproduct with water until asample of...the.wash liquor was free ofalkali. This product was identical with the4,4'-bis(benzimidazol-2-yl)stilbene described above.

The dihydrochloride was not soluble as such in any of the commonsolvents. The free'b'ascwas slightly soluble in lower alk-anols and inthe 2-(lower alkoxy)ethanols; it was more soluble inN,N'-dimethylfarmamide; and it was appreciably soluble (up to about 20%by weight) in alkaline 2-methoxyeth-anol. The free base reacts withorganic and inorganic acids to form the corresponding salts which a-reall waterrinsolublan- EXAMPLE 2 4,4-bis(benzimidazol-2-yl)stilbene In250 ml. flask fitted with an agitator and reflux condenser there wereplaced 131 g. of glacial acetic acid, 13g. of water, 2.56 g. (0.059mole) of aluminum chips, and l.18-g. of hydrochloric acid (20 -Baum).-The mixture was agitated vigorously and heated rapidly. Bubbling ofhydrogen from the mixture was vigorous when the temperature had reached70 C., and to the mixture there was then added 10.16 g. (0.02 mole) of4,4'-stilbene-di[carbox(ortho i nitroanilide)]. The reaction mixture wasrefluxed for 'four hours, after which there was added 1.76 g. (0.065mole) ofaluminum chips. The reaction mixture was-refluxed for a furtherperiod of sixteen hours. "The product,4,-4f-stilb'enedi[carbox(orthoamino'an ilide thus "formed was notisolated-in fthis instance. Instead, after removal of the outside sourceof heat, there was added to the reaction mixture 69.4 g. of hydrochloricacid Baum) and refluxing was continued for a final period of four hoursto'etfect the desired ring closure. The mixture was then cooled to -30C. and filtered. The solid thus collected was washed with water until asample of the wash liquor was-fr'ee of acid as determined by test withCongo red paper. The-product obtained, in this manner, which was4,4-bis-(ben- "zimidaZol-2-yl)stilbene dihydrochloride, weighed 9.7 g.It was identical with the dihydrochloride described above in Example 1.l Th 4,4-bis(benzimidazol wyl)stilbene' dihydrochlo ride was alsoobtained "in satisfactory yield when iron and 75-'- 90% acetic acid 'wassubstituted'ior the aluminum and glacialacetic acid in theabove-procedure. 3 Treatment of samples or the dihydr'ochloride obtainedabove with etharidlic' sodium hydroxide yielded in-each instance"4,4,-bis(benzimidazol 2 yl)stilbene, identical withthe base described inExample 1.

. EXAMPLE 3' p 4,4 bis(beniimiriizzbl-Z-YI)stilbene 1 To 271 .8 g. offinely ground (20 mesh) crude 4,4;-bis.- ;(benzimidazol-2-yl)stilbene-'dihydrochloride (obtained by the method described'above in Example 1)in .3050 g.. of 95% ethanolthere was added 216r10f250% aqueous sodiumhydroxide solution; This mixture was heated to reflux todissolve thesolid, and ,the solution was then filtered. toremove about 40 g. ofcreamy solid consisting chiefly inorganic salts which failed todissolve. The filtrate was- ,heated until about 2200 g. of alcohol hadbeen di-stilledofl and to the residue there was added 3.5 liters ofcoldwater in a thin stream; The mixture was cooled and filtered and theproduct thus collected was washed with water until a sample of thefiltrate was free, of alcohol.- There; was thus obtained 217 g. of4,4-bis(benzimidazol-Z-yDstilbene. Y

v In a 100 ml. flask there were placed 25 g. of 2-methoxyethanol, 6.96g. of sodium hydrosulfite, 2.54 g. of 4,4-

stilbenedi[carbox(ortho-nitroanilide)], 1.0 g. of 50% aqueous sodiumhydroxide solution, and 10 g. of water. This mixture, which was alkalineto phenolphthalein, was refluxed for two hours, after which time thesolution was no longeralkaline to phenolphthalein. A further quantity of50% aqueous sodium hydroxide solution "was'added sufiicient to make themixture alkaline and refluxing was resumed and continued 'for one andone-half hours. Ten ml. of concentrated hydrochloric acid was then addedand the mixture was refluxed for twenty minutes. The mixture was cooledto 20 C. and filtered, and the solid thus collected was washed withwater until the wash liquor was free of acid using Congo red paper. Theproduct thus obtained was 4,4'-bisQbenzimidazol-Z-yl)stilbene, identicalwith. the product described above in Example 1.

EXAMPLE" 5 4,4'-bis(benzimidazol-Z-yl)stilbehe A. To a well-stirredmixture of 91 g. of o-phenylenediarnine, 630 ml. of chlorobenzene, 100g. of sodium carbonate, and 250 ml. of waterheated to C. there was added.out of a heated dropping tunnel during a period of ten minutes asolution of;105 g..of 4,4-stilbenedicarbonyl chloride in 1400 .ml. ofchlorobenzene. The temperatureof the reaction mixture gradually roseduring the addition until refluxing was initiated. The mixture wasrefluxed for six hours, andthen cooled and filtered. The solid thuscollected was washed successively with 500 ml.

of hexane, 1000 ml. of a 0.25% aqueous solution of lorol?benzyldimethylamrnonium chloride, and finally water,

until the product was free of quaternary ammonium chloride. Thegrey-white product was then dried in an oven. There was thus obtained154g. of 4,4'-stilbenedi[carbox- (orthoaminoanilide)1 having thestructural formula This compound was weakly fluorescent; it= wasnot'soluble in the ordinary solvents. 1

B. In a .two liter, three-neck flask there were placed 800 ml. ofv2-methoxyethanol and- 200 g. of a wet paste of 92 g. of4,4f-stilbenedi[carbox(ortho-arninoanilide)] and 108 g. of-water.Thismixture was stirred and heated to reflux and 46 ml. of concentratedhydrochloric acid (about 38% by weight) was dropped into the mixtureduring a period of thirty-five minutes andthis reaction mixture wasrefluxed for eighteen hours. The reaction mixture was then cooled andfiltered and the solid thus collected was washed withv water'untilasample of the wash liquor was ,free of acid, using Congo red paper. Thewashed product, which was 4,4'-bis(benzimidazol2- yl)stilbenedihydrochloride,-- was suspended in 800 ml. of ethanol, 25 mLof 50%aqueous sodium hydroxide solution was added, and the mixture was heatedto reflux and filtered. The filtrate was diluted with three liters ofwater, and the solid which separated from solution was collected on afilter. There was thus obtained61.3 g. oi

but replacing the 'Z-methoxyethanol solvent with n-buta- 1101, the yieldof the 4,4-bis(-benzimidazolJ-yl)stilb'ene was considerably lower.

A. T o a three-liter, three-neck flask fitted with agitator andthermometer there were added 61.0 g. of N,N-dimethylaniiine, 63.9 g. of-2-nitro-4-methylaniline, and 707 *g. of chlorobenzene. This materialwas heated to 50 C. for'five minutes and then a solution of 60.4 g. of4,4- stilbenedicarbonyl chloride in 588 g. of 'ortho-dichlorobenzene wasadded. A solid began to'separate slowly from the reaction mixture andthe reaction temperature rose to 85 C. The reaction mixture was heatedat 85- 90 C. for one hour and then at 95-100 C. for twentyfour hours.The reaction mixture was cooled to room temperature and filtered; Thesolid product thus collectcd was washed with 67 g. of chlorobenzene, 97g. of methanol, and a 0.25%. aqueous solution of'lorolbenzyldimethylammonium chloride until a clear filtrate wasobtained. The product was then washed with water until the quaternaryammonium chloride had been re moved. The yellowproduct was dried in anoven. There was thus obtained 99 g. of 4,4'-stilbenedi[carbox(2-nitro-4-methylanilide )l which did not melt when heated at 320 C.

To a five-liter flask fitted with an agitator, thermometer, refluxcondenser and dropping funnel there were added 2250 ml. of 2-methoxyethanol and 99 g. (0.177 mole) of 4,4 -'stilbenedi[carbox.( 2nitro 4 methylanilide)]. This mixture was heated to reflux temperature,then heating was discontinued, and there was added a solution of 258 g.of stannous chloride dihydrate in 510 ml. of hydrochloric acid at such arate that refluxing was maintained by the heat of the reaction. Afterthis addition was completed, the reaction mixture was refluxed for sevenhours. The mixture was chilled in an 'icebox overnight and thenfiltered. The solid product thus collected was washed first with oneliter of 1% hydrochloric acid and then with Water until the solid wasfree of acid to 'Congo red. There was thus obtained 86.7 g. of 4,4'- 7bi'sl5'(or 6) -miethylbenzimidazol 2 yllstilbene dihydrochloride. Thissalt was suspended in 9 19 nib-of 2-methoxyet'hanol and the mixture washeated to C. with stirring. There was then" added 36 g. of 50% aqueoussodium hydroxide solution and'the mixture wasslowly heated to refluxtemperature. The mixture was filtered to remove insoluble material,consisting chiefly of in- "'12 on a filter and freed of alkali 'bywashingwith water. There was thus obtained 61.8 .g. of 4;4-bi's['5(o'r6')- methylbenzimidazol-Z-yl] -"stilbene.

. 7 CH 0cm HOO/ OCH:

A. To a mixture of 61.0 g. of N,N-dimethylaniline, 70.6 g. of2-nitro-4-methoxyaniline, and 640 ml. of chlorobenzene heated to 50 C.there was added slowly with stirring over a period of eight minutes, ahot (120-130 C.) solution of 61.1 g. of 4,4'-stilbenedicarbonyl chloridein 467 .ml. ofchlorobenzene. The remnants of the acid chloride solutionwere washed from its container into the reaction mixture with anadditional 61 m1. of chlorobenzene. The mixture was heated at -95 C. forone hour and then at -100 C. for twenty-four hours... The mixture wasthen cooled to room temperature (about 25 C.) and filtered, and thesolid thus collected was washed successively with 61 ml. ofchlorobenzene, 122 ml. e f-methano], and a warm (50 C.) 0.25% aqueoussolution of lorolbenzyldimethylammonium chloride until the wash liquorwas free of chlorobenzene. The solid was finally washed with one literof warm (50 C.) water to remove the quaternary ammonium chloride. Therewas thus obtained 111.2 g. of 4,4'-stilbenedi-[carbox(2-nitro-4-rnethoxyanilide)]- as a yellow solid which melted at 311- 318 C. 1

B. A mixture of 2,324 ml. of Z-methoxyethanol and .104 g. of4,4-stilbenediLcarbox(2-nitro 4-methoxyaniv lide)] was heated to reflux,then heating was discontinued and a solution of 266 g. of stannouschloride dihydrate in 5.27 ml. of concentrated hydrochloric acid wasadded slowly with stirring over a period of .seven minutes. 'Refluxingwas then resumed and continued for fifteen hours. The reaction mixturewas cooled to 15 C. and filtered, and the solid thus collected. waswashed with water until free of acid and dried. This product, which was4,4" bis[5(0r 6)'methoxybenzimidazo1-2-y1]stilbene diliydrochloride, wassuspended in 1076 ml. of Z-tnethoxyethandl and heated'to 60 C. To thismixture there was added 50.6 g. of 50% aqueous sodium hydroxidesolution. The

temperature of the mixture rose to 75 C. and almost all of the soliddissolved. The mixture was heated to reflux temperature and filtered.The residue thus removed was washed with 106 ml. ofboiling.Z-mcthoxyethandl, and the washings were combined with thefiltrate. This solution was slowly diluted with eleven liters of warm('60 C.) water. The yellow solid'which precipitated from solutionwas'collected on a filter, washed with water until free of alkali, andthen dried in an oven. The product thus obtained, which was,4,4'--bis[5(or 6)-methoxybenzimid-az'ol 2 yll'stilbene, weighed 81.2 g.It was soluble in polyethyleneglycol, 'HOCI-l (CH OCH CH OH, of averagemolecular weight 200 (Carbowax 200) containing alkali; The fluorescenceof this solution, though yellower than that exhibited by4,4'-bis-('benzimidazola yl)stil bene, was far more intense than that ofthe latter com pound under similar conditions.

-13 V EXAMPLE'8.=- 4.4'-bis (or 6) -chlorobenzimidazol-Z-jl] s ilb A. Amixture of 72.5 g'. of 2-nitro-4-chloroaniline, 61.0 g. ofN,N-dimethylaniline, and .640 ml. of: chlorobenzene was heated to 50 C.and there was then added slowly over a period of five minutes, 'withstirring, a hot (125- 130" C.) solution-of 61.0 g. of'4,4-stilbenedicarbonyl chloride 'in 474 ml. of chlorobenzene. Theresidual acid chloride solution'was washed from its container into themixture with 61 ml. of chlorobenzene. The mixture was heated at 85-90 C.for one hour and then at 75100 C. for twenty-four hours. The reactionmixture was cooled to room temperature '(about 25 C.) and filtered. The

solid thus collected was washed successively with 61 ml. ofchlorobenzene, 122 ml. of methanol, and sufficient warm (50 C.) 0.25%aqueous solution of lorolbenzyldimethylammonium chloride toyieldcolorless washings. The solid was finally washed with water until thequaternary ammonium chloride had been removed and the product was dried.There was thus obtained 107.2 g. of 4,4' stilbenedi [carbox(2nitro-4-chloroanilide) B. A mixture of 100 g. of4,4'-stilbenedi[carbox(2- nitro-4-chloroanilide)] and 2200 ml. of2-methoxyethanol was heated to reflux temperature, then the source ofheat was removed, and there was addedwith stirring a solution of 252.3g. of stannous chloride dihydrate in 499 ml. of concentratedhydrochloric acid at such a rate as to maintain rapid refluxing. Thereaction mixture was refluxed for twenty hours. and was then cooled'to25 c C. :and filtered. The. solid thus collected was washed with wateruntil free of acidfand dried. The yellow. product thus obtained,whichwas 4,4'-bis[5(or 6)-chlorob enzimidaiol-Zyllstilbenedihydrochloride-was, mixed with 1250 ml. ,o'f19;5% ethanol and 64 g. of.-50% aqueous sodium hydroxide solution. This mixture wasrefluxed untilsubstantiallyfall of the yellowsolidhad dissolved and then filtered hotto remove insoluble inorganic salts. The solid residue on the filter waswashed with 100' ml. of 95% ethanol and all of the filtrates werecombined and were then diluted slowly/with seven liters..of warm (50 C.)

' 14 1 A. To a hot C.) and stirred mixtureof 48 g. ofN-methyl-ortho-phenylenediamine, 294 ml. of chlorobenzene, 46.6 g. ofsodium carbonate and 117 ml. of water there was added slowly from aheated dropping funnel a solution of 51.7 g. of.4,4'.-stilbenedicarbonylchloride in 717,- ml. of chlorobenzene. This addition,

which required about twenty minutes, was followed by e a six-hour periodof refluxing of the reaction mixture. A small quantity of aqueous sodiumcarbonatesolution was addedto the mixture during the course of thereflux period to keep it alkaline to phenolphthalein. ,The reactionmixture was cooled to 5 "I C. and filtered,v and the solid thuscollected" was washed with hexane andthen with water. The solid was thenslurried-in hexane and filtered. The product thus obtained, which was4,4- stilbenedi{carbox [ortho(methylamino) anilide] weighed 41.0 g. g

B. A mixture of 41.0 g. of 4,4-stilbenedi{carbox[ortho-(methylamino)anilide]} and 1158 ml. of Z-methoxyethanol was heated toreflux temperature and 115.8 ml. of concentrated hydrochloric acid was,added dropwise with sti1ring to the refluxing mixture. All of the'soliddissolved during this addition. The solution was refluxed for a furtherperiod ofone hour. The-solution was then distilled to remove abouttwo-thirds of the 2-methoxyethanol and the residue was chilled overnightin arefrigerator. The solid which had separated from solutionwas thencollected on a filter. There was thus obtained 24.4 g. of4,4'-bis(1-methylbenzimidazol-2-yl)stilbene dihydrochloride. A mixtureof this product and 965 ml. of Z-methbxyethanol was heated to refluxtemperature and 450 ml. of concentrated hydrochloric acid was slowlyadded with stirring to dissolve the solid. The solution thus obtainedwas poured into an agitated mixture of 550 g. of 50% aqueous sodiumhydroxide solution: and 500 ml. of ethanol. The mixture became hot and acream colored solid separatdfrom solution. The mixture was distilleduntil 574 ml. of distillate had been collected. The residue was cooledto 50? C. and 1250 ml. of water was added very slowly with goodagitation. The mixture was cooled to room temperature while continuingthe agitation and was then filtered. The collected solid was washed withwater until free of alkali and dried. There was thus obtained4,4'-bis(l-methylbenzimidazol- 2-yl) stilbene.

EXAMPLE 10 M ethylation of 4,4'-bis(benzimidazol-Z-yl)stilbene A. To asolution of 10.3 g. (0.025 mole) of 4,4'-bis-(benzimidazol-2-yl)stilbene in ml. of Z-methoxyethanol there was added 4ml. of a 50% aqueous solution I of sodium hydroxide. The mixture washeated to 65 C.

water. The pale yellow solid which separated from solution was collectedon a filtenwashed free of alkali with water and dried. There was thusobtained 83.2 g. of 4,4- bis 5- (or 6) -chlorobenzimidazol-2-yl]stilbene.

EXAMPLE 9 i 4,4'-bis(1-mthylber zimidazo'm yl)stilbene and 3.14-g.(0.025 mole) of methyl sulfate was added. The reaction mixture washeated at 70 C. for three hours and then 1.5 ml. of water was added. Thereaction mixture was cooled to 20 C. and filtered. The solid thuscollected was washedfwith water and then dried at 70 C. Therewas thusobtained 9.9 g. of 4 (benzimidazol-2-yl)-4-(l-methylbenzimidazol-Z-yl)stilbene, having the structural formula Z ih-Z B; A mixture or. 817' g. (0.021 mole). of4,'4'-bis'(benzimida'zol-Z-yljstilbene, 65 ml. of Z-methoxyethanol, and

4.46 ml.- of a 50% aqueous solution of sodium hydroxide .washeated to 65C.'and 3.19 g. (0.025 mole) of methyl sulfate -was added. The reactionmixture was heated at .70 C. for onehour and then: 3.19 (0.025 mole) ofmethyl sulfatewas added, after which the mixture was EXAMPLE 11 VCarboxymethylationof 4,4-bis(benzimidazol-Z-yl)stilbene To a 100 ml.flask fitted with an agitator and a reflux condenser there were. added4.84 g. (0.0113 mole) of 4,4-bis(benzimidazol-2-yl) stilbene, 20 ml. ofZ-methoxyethanol), and 3.0 g. of 50% aqueous sodium hydroxide solution.This mixture washeated until the solid went into solution, and thesolution thus obtained was cooled to about 50 C. and 0.95 g. (0.012mole) of monochloroacetic acidwas added. The reaction mixture wasrefluxed for two hours; cooled to about 50 C. and another 0.95 g.monochloroacetic acid was added. The reaction mixture was refluxed for afurther period of two hours and then cooled to room temperature (about25 C.). Fifty ml. of water wasaddeddropwise to the reaction mixture, andthe solid which had separated from solution was collected on a filter,washed with about 60 ml. of water, and dried in an oven. There, was thusobtained 3.2 g. of 4-benzimidazol 2-yl) -4'-[l-(carboxymethyl)benzimidazol-Z-yllstilbene, having the structuralformula I V GHserG O OH 'Iihiscompound reacts with bases, for example.alkali and alkaline earth, hydroxides, to form the correspondingcarboxylate salts.- a

EXAMPLE 12 "Carboxymethylation. of 4-(benzimida zol-2 -yl) -4'-(l-methy[banzimidazol-Z-yl)stilbene A mixture of 4.26 g. (0.01 mole) of4-(benzimidazol-2- yl)-4-( l-methylbenzimidazol-Z-yl)stilbene, 1 ml. of50% aqueous sodiurn hydroxide solutiom-and 25 ml. of 2-methoxyethanolwas heated to 80. C. to dissolve the solid and 0.95 g. (0.012 mole) ofchloroacetic acid was added. A yellow precipitate appeared immediatelyin the reaction mixture. The mixture was refluxed for two hours, thencooled to 90 C. and another 0.95 g. of chloroacetic acid was added. Themixture was refluxed for two hours, then cooled to 90 C. and 50 ml. ofwater was added. The mixture was then diluted with 200 ml. of hot water,cooled to room temperature, and filtered. The solid thus collected waswashed with water and dried. There was thus obtained 4.6 g. of4-[l-(carboxy-methyl)benzimidimidazoLZ-yhstilbne, 1.6 g. of. a 50%aqueous solution azol-2-yl] -4'-( l-methy1benzimidazol-2-yl)stilbenehaving the structural formula. 7 3

I CH:

EXAMP E 1,3- Cyanoethylati'on of 4,'4-bis(benzimidazol-Z-yl)stilbene-iA. A mixtureof 4.1' g. (0.01 mole) of 4,4-bis(benzi,-

of, sodium hydroxide, and 25 ml. ofZ-methoxyethanol was heated ,todissolve the solid. To the warm (50 C.) solutionv was added 0.53 g. 0.0lmole) of acrylonitrile and this reaction mixture was heated at 50 C. fortwo hours. There was thus produced 4 (ben zimida zol 2 yl) 4'-[I-(Z-cyanoethyl)benzimidazol-2 yl]stilbene, having the structuralformula CH V JQ This compound was soluble in 10% alkaline ethanol.

B. A mixture of 4.1 g. (0.01 mole) of 4,4bis(benzimidazol-2-yl)stilbene,1.6 g. of a 5 0% aqueous solution of sodium hydroxide, and 25 ml. ofZ-methoxyethanol was heated to-dissolve the solid. To the warm (50 vC.)solution was added 2.64 ml. (0.04 mole) of acrylonit'rile and thisreaction mixture was heated at 50 C. for two '17 ,7ethyl)benzimidazol-2-yl]stilbene, having the structural formula N CHJHr-CHrCN To the reaction mixture containing this product were added 1.6g. of a 50% aqueous solution of sodium hydroxide and 5 ml. of water andthe mixture was refluxed for two hours to hydrolyze the cyano groups.The reaction mixture was cooled to 50 C., diluted with 200 ml. of waterand filtered. The solid thus collected was washed with water and dried.There was thus obtained 4.1 g. of4,4'-bis[1-(2-carboxyethyl)benzimidazol-Z-yl] stilbene, having thestructural formula (IJHPCHPCOOH This compound was soluble in alkalineethanol. It had an especially high substantivity to cellulose acetate.

EXAMPLE 14 Cyanoethylation .of 4-(benzimidazol-2-yl) -4-(1-methylbenzimidazol-Z-yl)stilbene A mixture of 4.26 g. (0.01 mole) of4-(benzimidazol-.

30% aqueous solution of sodium hydroxide, and 25 ml. of Z-methoxyethanolwas heated to 50 C. to dissolve the solid. To this solution were added0.53 g. (0.01 mole) of acrylonitrile and about 20 mg. of cuprouschloride (to serve as acatalyst for the alkylation and to inhibitpolymerization of the acrylonitrile) and the mixture was heated at 50 C.for two hours. There was thus produced4-[I-(Z-cyanoethyl)benzimidazol-Z-yl] 4' (1methylbenzimidazol-2-yl)stilbene, having the structural formula t 3 O\N/ The reaction mixture containing this product was mixed with5 ml. ofwater and the mixture was refluxed for two hours to hydrolyze the cyanogroup. 'The mixture was mixed with 250 ml. of water and filtered. Thesolid thus collected was washed with water and dried in an oven at C.There was thus obtained 4.3 g. of4-[1-(2-carboxyethyl)benzimidazol-2-yl] 4 (1methylbenzimidazol-2-yl)-stilbene having the structural formulaCHrCHs-CO OH EXAMPLE 15 Chlorobenzylation of4,4'-bistbenzimidazol-Z-yl)stilbene a filter and dried at 70 C. Thisproduct, which weighed 6.5 g. and melted at 270-280 C., was a mixturewhich consisted chiefly of the N,N-dialkylated derivative and a lesseramount of the monoalkylated compound, namely 4 (benzimidazol 2 yl) 4' [1(ortho chlorobenzyl)benzimidazol 2 yl] stilbene having the structuralformula The separation of these two products can be carried out byconventional fractionation, as by recrystallization. For example, forrecovery of the N,N-dialkylated product, the mixture obtained above wasrecrystallized first from 200 ml. of N,N-dimethylformamide and then from40 ml. of boiling ortho-dichlorobenzene, followed by washing withbenzene andether, and drying under reduced pressure at-l00 C. The nearlycolorless crystalline needles thus obtained consisted of4,4'-bis[1-(ortho- The reaction mixture chlorobenzyl)benzimidazol 2yllstilbene, having the structural formula EXAMPLE 16 Allylation 07"4,4-bis(benzimidazol-Z-yl)stilbene To a mixture of 60 g. (0.147 mole) of4,4-bis(benzimidazol-2-yl)stilbene, 280 ml. of Z-methoxyethanol, and 39g. of a 50% aqueous solution of sodium hydroxide heated at 50 C. therewas added dropwise, over a period of one hour, 12 g. (0.0157 mole) ofallyl chloride. The reaction mixture was refluxed for sixteen hours andthen was diluted with 280 ml. of water. The solid which had separatedfrom solution was collected on a filter and washedfree of alkali withwater. This solid, which weighed 60 g., consisted of the crude'rnonoallylation product; it was purified as follows. The solid wasdissolved in 400ml. of N,N-dimethylformamide and the resulting solutionwas filtered to remove undissolved 4,4- bis(benzimidazol-2yl)stilbene.The filtrate was poured into a large volume of water and the solid whichseparated from solution was collected on a filter. There was obtained inthis manner, as a yellow solid, the purified 4-benzimidazol-2yl-4'-(l-allylbenzimidazol-2-yl) stilbene, having the structural formula Z il-Z 3HrCH=CH= B. By interaction of the monoallylation product describedabove with a second molecular equivalent of allyl chloride, there isobtained 4,4'-bis(l-allylbenzirnidazol- 2-yl)stilbene, having thestructural formula 20 EXAMPLE 17 Hydroxyethylhtion of4,4'-bis(benzimidazol-Z-yl)stilberte' To a 50 ml. ground glasswide-mouth flask equipped with a condenser the barrel of which served asa bearing for an agitator paddle there were added 4.1 g. (0.01 mole) of4,4'-bis(benzimidazol-Z-yl)stilbene, 16.5 g. of 2-methoxyethanol and 1.8g. of a 50% aqueous solution of sodium hydroxide. After all of the solidhad gone into solution there was added 1.7 g. (0.0212 mole) of ethylenechlorohydrin. The reaction mixture was slurried' and refluxed for onehour after which period the reaction mixture was transferred to a beakerand heated on a water bath until approximately half of the solvent hadevaporated. There was then added 30 ml. of water and the mixture wasallowed to cool to room temperature. The yellow solid which hadseparated from solution was collected on a filter and washed With wateruntil a sample of the wash liquor was colorless and free of alkali. Theproduct thusobtained, which weighed 4.1 g., was a yellow solidwhich didnot melt at 350 C.

droxyethyl)benzirnidazol-Z-yl]stilbene, having the structural formula Zi l-Z which was soluble in aqueous alkaline ethanol solution, with smallamounts of unreacted 4,4-bis(henzimidazol- 2-yl)stilbene and4,4-bis[1-(2-hydroxyethyl)benzimidazol-Z-yllstilbene, having thestructural formula l omomon The dialkylated product was' insoluble inaqueous al-.

kaline ethanol solution and very slightly soluble in glacial aceticacid.

EXAMPLE 18 Dihydroxypropylation of 4,4-bis[5(0r6)-methylbenzimidazol-Z-yl] stilbene [5 0r 6) -methylbenzimidaZ0l-2-yl]-4'-[ 1- (2,3 -dihydroxy 21 propyl)-(or6)-methylbenzimid'aZol-2-yl]stilbene, Y having the structural formula Tothe reaction mixture containing the above compound, there was added asecond portion of 2.08 -g. of 2, 3-dihydroxypropyl chloride and themixture was refluxed for one and one-half hours. The mixture was thencooled and diluted with 575 ml. of warm (50 C.) water and filtered. Thesolid thus collected was washed with water until free of alkali and thendried in an oven. There was thus obtained 8.9 g. of solid consistingchiefly of the monoalkylated compound above and 4-[5 (or 6)-methylbenzimidazol-Z-yl]-4'-{1-[2-hydroxy-3-(2,3-dihydroxypropoxy)propyl]-5 (or 6)methylbenzimidazol-2-yl}stilbene having the structural formula and asmall amount of unreacted 4,4'-bis[5 (or6)-methylbenzimidazol-Z-yl]stilbene starting material.

EXAMPLE 19 w v Dihydroxypropylatiori of 4,4-bz 's[5(br 6)'-methbxybenzimidazol-Z-yl]stilbene To a solution of 10.8 g. of 4,4'-bis[5('or 6)-methoxybenzimidazol-Z-yl]stilbene, 5.15 g. of a 50% aqueoussolution of sodium hydroxide and 32.0 g. of Z-methoxy ethanol at 50 C.there was added with. good stirring 2.08 g. of 2,3-dihydroxypropylchloride and the mixture was refluxed for one and one-half hours. Therewas thus produced 4-[5(or 6)-methoxybenzimidazol-2-yl]- 4' [1(2,3dihydroxypropyD-S (or 6)-methoxybenzimidazol-Z-yllstilbene, having thestructural formula lHr-GHOH-CHaOH 290 ml. of warm (50 C.) water.

To the reaction mixture containing the above 'compound there was added asecond 2.08 g. portion of 2,3-dihydroxypropyl chloride. one-half hoursand then was cooled andv diluted with The diluted mixture was filteredand the solid thus collected was washed with water until free of alkali,and dried. There was thus obtained 12 g. of yellow solid which consistedchiefly of the above-mentioned monoalkylated product and an O-alkylation derivative thereof, namely 4-[5(or6)-methoxybenzimidazol-Z-yl] -4'-{1-[2-hydroxy-3-(2,3-dihydroxypropoxy)propyl] 5 (or6)-methoxybenezim.idazol-2-yl}- stilbene having the structural formuladHr-O-GHq-CHOH-CHzOH along with some unalkylated starting material.

EXAMPLE 20 Dihydroxypropylation of 4,4-bis[5 (or 6)-chlorobenzimidazol-Z-yl]stilbene OHz-CHOH-CHzOH The reaction mixturecontaining the above compound was cooled to 50 C., a second portion of11.5 g. of 2,3-dihydroxypropyl chloride was added, and the mixture wasrefluxed for one and one-half hours. The mixture was then cooled to 60C. and 1800 ml. of warm (50 C.) water was added in a thin stream withgood agitation. The diluted mixture was filtered tocollect the yellowsolid which precipitated. The collected solid was washed free of alkaliwith water and dried. There was thus obtained 54.6 g. of yellow productconsisting chiefly of the monoalkylated product mentioned above and 4-[5(or 6)- chlorobenzimidazol 2 yl] 4' {1- [2-hydroxy-3-(2,3-di- Themixture was refluxed for one and p 23' hydroxypropoxy)propy-l] (0r6),-chlorobenzimidazol-2- yl}stilbene' having the structural-formulatogether with some unalkylated starting material. This 20- product. was,less soluble in alkaline ethanol solution than were, the correspondingunchlorinated compound (Example 28B); 311(1111116 dimethoxy analog(Example 19).

EXAMPLE 21 Hydroxye thoxy hydroxypropylationof 4,4'-bis(benzimidazol-Z-yl) stilbene CHf-CHOH-GHr-O ornontou a furtherperiod of two hours.

To the warm (42 C.); reaction mixture containing the above compoundthere was added a further portion of 6.16 g. (0.04 mole) of2-hydroxy-2-(Z-hydroxyethoxy) propyl chloride and the mixture wasrefluxed for one and one-half hours. There was then distilled from thereaction mixture 300 ml. of solvent, the residue in the still was cooledto 60 C., and 600 m1. of warm (60 C.) water was added (in subsequentpreparations the mixture was seeded at this point with a small amount ofthe expected monoalkylation product noted above). The mixture, whichcontained solid which had separated from solution, was stirredvigorously, and then cooled to room temperature (about C.) and filtered.The solid thus collected was washed with water until a sample of thefiltrate was free of alkali. There was thus obtained 96 g. of paleyellow product which consisted chiefly of 4- (benzimidazol 2 yl)4f-{;l.-[2-hydroxy-3-(2-hydroxyethoxy)-propyl]benzimidazol-2-yl}stilbene together with small amounts of theO-alkylated derivative thereof having the structural formula andum'eacted 4,4'-bis(benzimidazol-2-yl)stilbene starting material. Theproduct was slightly soluble in ethanol, acetone, and 2-methoxyethanoland insoluble in nonpolar solvents. It was soluble in alkaline ethanolsolutions.

EXAMPLE 22 Dihydroxypropoxy-hydrqxypropylation of4,4'-bis(benzimidazol-Z-yl) stilbene Toa '100 ml; flask fitted with astirrer and reflux condenser there was added 8.2- g. of4,4'-bis(benzimidazol'-2-yl)-stilben'e, 33 ml. of 2-methoxyethanol, and4 .0 g: of a aqueous sodium hydroxide solution and the mixture washeated to dissolve the solid; The solution thus obtained was cooled. to50 C; and there was added. 6.1 g. of 2-hydroxy-3-(2,3-dihydroxypropoxy)-propyl chloride. The reaction mixture was refluxed for two hours, thencooled to 50 C., a further portion of 1.2 g. ofZ-hydroxy-3-(2,3-dihydroxypropoxy)propyl chloride was added, and themixture. was refluxed for The reaction mixture was then cooled to 50 C.and 200ml. of cold water was added slowly. The solid which had separatedfrom solution was collected on a filter, washed free of alkali withwater and dried in an oven. There was thus obtained 9.2 g. of yellowsolid which consisted chiefly of 4 (benzirnidazol 2-yl)-4'-{1-[2-hydroxy-3(2,3-dihydroxypropoxy)propyl]benzimidazol2y1}stilbene(identical with the compound obtained in Example 28B by a differentmethod).

v 25 EXAMPLE 23 Hydroxyethoxyethoxy hydroryproplation of 4,4"-Bis(benzimidazol-Z-yl)stilbene To a 100 ml. flask fitted with a stirrer andreflux condenser there was added 8.2 g. of 4,4-bis(benzimidazol-2-yl)stilbene, 33 ml. of 2-methoxyethanol, and 4.0 g. of a 50% aqueoussodium hydroxidesolution and the mixture was heated to dissolve thesolid. The temperature of the solution thus obtained was adjusted to 50C. and there was added 7.25 g. of 2-hydroxy-3-[2-(2hydroxyethoxy)ethoxy] propyl chloride. The reaction mixture was refluxedfor two hours and then cooled to 50 C. There was added a further portionof 1.4 g. of 2-hydroxy- 3-[2-(2-hydroxyethoxy)-ethoxy]propyl chlorideand the mixture was refluxed for one and one-half hours. To the reactionmixture was added 300 ml. of cold water with stirring. The solid whichhad separated from solution was collected on a filter, washed free ofalkali with water and dried in an oven. There was thus obtained 9.8 g.of product consisting chiefly of 4-(benzimidazol-2-yl)-4'-{1- {2hydroxy-3- [2- (hydroxyethoxy) ethoxy]propyl}benzimidazol-2-yl}stilbene, having the structural 'formulaEXAMPLE 24 Hydroxyethylation of (benzimidazol 2 yl)-4-1-[2-hydroxy 3(2-hydroxyethoxy)propyl] benzimidazol-Z-yl I stilbene To a 200 ml.three-neck flaslt fitted with a magnetic stirrer, gas one-inlet tube andU-tube manometer filled with one inchof mercury there were added 10.6 g.of 4- (benzimidazol-Z-yl) -'4 {1 [2-hydroxy-3-(2-hydroxyethoxy)propyl]benzimidazol-2-yl}-stilbene, 90 ml. of 95% ethanol, and 4.5 g. of a 50%aqueous sodium hydroxide solution and the mixture was heated to 75 C. todissolve the solid. The solution thus obtained was cooled and maintainedat 70-75 C. and ethylene oxide was passed into the mixture for 45 min.,during which time the mixture absorbed 6.3 g. of ethylene oxide. Almostall of the absorption of ethylene oxide occurred during the first thirtyminutes of this period. The reaction mixture was then cooled to 40 C.and diluted slowly with 300 ml. of water at 40 C. The diluted mixturewas cooled to 20 C. and the solid which had separated from solution wascollected on a filter and washed free of alkali with water. There wasthus obtained 11.6 g. of yellow solid which consisted chiefly of4-(benzimidazol-2-yl)-4- 1 {2-hydroxy-3- [2- (Z-hydroxyethoxy) ethoxy]propyl} benzimidazol-Z-yl]stilbene.

EXAMPLE 25 v Sulfo-hydroxypropylation of 4,4"-bis(benzimidazl-2-yl)-stilbene To a 100ml. flask fitted with a stirrer and reflux condenser.there was added 4.84 g. of 4,4'-bis(benzirnidazol 2-yl)stilbenedihydrochloride, 25 ml. of Z-methoxyethalid, and' 3.6 g. of a 50%aqueous sodium hydroxide solution. This solution was heated to dissolveall of the solid and the solution thus obtained was cooled to 50 C.There was then added 4.4 g. of sodium 2-hydroxy-3-chloropropanesulfonate and the reaction mixture was refluxed for twohours. Forty ml. of water was added and the mixture was cooled in an icebath. Two ml. of glacial acetic acid was added to the cooled mixture tofacilitate the coagulation of the solid which had separated fromsolution, and the mixture was filtered. The solid thus collected waswashed with water and dried in an oven. There was thus obtained 5 g. ofsolid which con sisted chiefly of they sodium salt of the4-(benzimidazol-Z- yl) 4' [1-(2-hydroxy-2-sulfopropyl)benzimidazol-Z-yllstilbene having the formula CHOH EXAMPLE 26Hydroxyethoxyethoxy-hydroxypropylation of 4,4'-[5(0r 6)-chI0r0benzimidaz0l-2-yl]stilbene A mixture of 10.0 g. of 4,4'-[5(or 6)chlorobenzimidazol-2-yllstilbene, 41.8 ml. of Z-methoxyethanol, and 5.7g. of a 50% aqueous solution of sodium hydroxide was refluxed until thesolid had dissolved. The resulting solution Was cooled to 50 C., 6.0 g.of 2-hydroxy-3-[2- (Z-hydroxyethoxy) ethoxylpropyl chloride was added,and the mixture was refluxed for one and one-half hours. There was thusproduced 4-[5(or 6)-chlorobenzimidazol- 2yl]-4-[1-{2-hydroxy-3-[2-(2-hydroxyethoxy)ethoxy]- propyl}-5 (or6)-chlorobenzimidazol-2-yl]stilbene, having the structural formula Z ii-Z orn-o-omom-o-omomon [1(2,12,19-trihydroxy-4,7,10,14,17-pentaoxanonadecy1- 27 (0):6)i-chlorobenzimidazol-2-yll stilbene, an O-alkylated derivative of the.N-monoalkylated compound above.

EXAMPLE 27 Hydroxyethoxy-hydroxypropylation of a mixture of 4,4-bis'-(benzimidazol-Z-yl)stilbene .and 4-(benzimidazol-2- yl) -4-(1-methylbenzimidazol-Z-yl)stilbene 8.0 g. of crude4-(benZimidazol-2-yl)-4'-(l-methylbenzimidazol-Z-yDstilbene whichcontained some 4,4'-bis- (benzimidazol-Z-yl)stilbene was mixed with 80ml. of 2-metl1'oxyethanol and 2.98 g. of a 50% aqueous solution ofsodium hydroxide and the mixture was heated to dissolve the solid. Tothe hot (70 C.) solution there was added 2.87 g. of2-hydroxy-3-(2-hydroxyethoxy)- propyl chloride and the mixture wasrefluxed for two hours. The reaction mixture was cooled to about 60 C.and a further 2.87 g. portion of 2-hydroxy-3-(2-hydroxyethoxy)-propylchloride was added. The mixture was refluxed for two hours, then cooledto 50 C., and 200 ml. of water was added. A gum separated from solutionand this solidified on stirring. To the mixture there was added 300 ml.of water and the solid was collected on a filter, washed with water, anddried at 70 C. There was thus obtained 10.5 g. of product whichconsisted chiefly of a mixture of4-(1-methylbenzimidazol-2-yl)-4'-{1-[2- hydroxy-3-(2hydroxyethoxy)propy1]benzimidazol-yl}- stilbene, having the structuralformula CHOH CHrQ-CH CHgOH and the O-alkylate derivative thereof havingthe structural formula 28 EXAMPLE 2s Dihydroxypropylation of4,4'-bis(benzimidazol-Z-yl)r stilbene.

tator, thermometer, and condenser there were placedv 317 g. (0.78 mole)of 4,4'-bis(benzimidazol-2-yl)stilbene, 1330 g. of Z-methoxyethanol, and214g. of a aqueous solution ofsodium hydroxide. After all of thesolidhadgone into solution, the temperature of the mixture was adjustedto 50 C. and there was. then added in one portion.86.5 g. (0.78 mole)of2-,3-dihydroxypropyl chloride. The reaction mixture was refluxed for.one and one-half hours.. There wasthus produced 4-(benzimidazol 2yl)-4-[1-(2,3-dihydroxypropyl)benzimidazol-2-yl]stilbene, a yellowcompound having the structural formula This product. contained. someunreacted 4,4-bis(benzimidazol-2-yl)stilbene.

B. The reactionmixture was cooled to 42 C., and another 86.5 g. portionof 2,3-dihydroxypropyl chloride was. added. Thereaction mixture wasrefluxed for a further period of one and one-half hours. and then 465together with a small amount of. 4'-(benzimidazol 2-yl)*4- 701ml..of.water was addedslowly. The mixture was heated {1 [2hydroxy-3(2-hydroxyethoxy)propyl]benzimidazol-2-yl}stilbene derived fromthe 4,4 'bis(benzimidazol- 2-yl)stilbene in the starting material. Themixture of compound obtainedin this reaction was soluble in, glacialacetic. acid.

to remove 2050 ml. of solvent .by distillation; and to the residue inthe still there was added 2200 ml. of warm C.) Water. The dilutedmixture was cooled to 251 C; and. filteredl to eollectthe' solid productwhich had separated from solution. The filter cake was washed 29 withwater until a sample of the wash liquor was free of alkali as determinedby testing with phenolphthalein paper and then the solid was dried.There was thus obtained 415 g. of yellow material in which thedialkylated product consisted chiefly of the O-(dihydroxypropylated)derivatives of the monoalkylated compound, as for example4-(benzimidazol-2-yl)-4-{1-[2 hydroxy 3(2,3-dihydroxypropoxy]propylbenzirnidazol 2 yl} stilbene, having thestructural formula The yellow product also contained some of themonoalkylated compound as well as a small amount of 4,4-bis(benezimidazol-2-yl)-stilbene. The product was slightly soluble inZ-methoxyethanol and 2-ethoxyethanol and insoluble in methanol, ethanol,and glacial acetic acid. It was soluble in N,N-dimethylformamide to theextent of about 20%. In monosodium salt form, the product was verysoluble in alkaline ethanol and alkaline Z-ethoxyethanol; in the formersolvent, the solubility was about 20%, and in the latter, about 33%.

C. The mixture of products described in part B above was useful withoutfurther treatment as a whitening and brightening agent. However, forincorporation into white solid detergents, I prefer to remove oreliminate from the mixture all unreacted4,4'-bis(benzimidazol-2-yl)stilbene starting material. I have found thatthe unalkylated compounds of Formula I may cause yellowing of'some solidwhite detergents containing 10-20% of water and, although this does notcause any diminution of the whitening and brightening properties of thedetergent composition, the'detergents thereby may become lessmarketable. The white color of the yellowed detergent is however readilyrestored by drying to bring the water content thereof below about 10% byWeight. The following method illustrates the removal of4,4-bis(benzimidazol- 2-yl) stilbene from the mixture of products.

A suspension of 5 g. of the product of part B in 30 ml. of glacialacetic acid was stirred for one hour. The mixture was then filtered tocollect insoluble material, which consisted of 4,4'-bis(benzimidazol-2-yl)stilbene diacetate. The filtrate was diluted with 200ml. of water. Centrifugation caused the separation of a very finelydivided solid from the mixture. The supernatant liquid was made basic bytreatment with ammonia, and the mixture was boiled to coagulate the finepowder and then was cooled and filtered. The precipitate thus collectedwas washed with water until free of ammonia and then dried. This solid,which weighed 2.7 g. was suspended in- 150 ml. of 95% ethanol, themixture was boiled for fifteen minutes, and the solution thus obtainedfiltered by gravity while hot. The insoluble residue thus removed waswashed with a few ml. of ethanol. The wash liquor and filtrate werecombined, concentrated to about 75 ml., and diluted with a small amountof Water until crystals began to appear. The solution was cooled andfiltered to collect 1.8 g. of solid. Recrystallization of this producttwice from N,N-dimethylformamide and once from 2-ethoxyethanol yielded4-(benzimidazol-2-yl-4-{1- [2 hydroxy 3(2,3-dihydroxypropoxy)propyllbenzimidazol-2-yl}sti1bene, which melted at225 C.

D. Further alkylation" of themixture of products obtained in part Babove yielded O-alkylated derivatives of the 4-benzimidazol 2yl-4'-{1-[2-hydroxy-3-(2,3-dihydroxypropoxy)propyllbenzimidazol 2yl}stilbene component and resulted in the elimination of the4,4-bis(benzimidazol-2-yl)stilbene component by converting it to N-monoalkylated and N,N-dialkylated derivatives. As in the case of theproduct purified by the method of part C above, these4,4'-bis(benzimidazol-Z-yl)stilbene-free mixtures were found to beespecially useful as whitening and brightening agents for incorporationinto white solid detergents. It was found that the progressiveelimination of the N,N'-unalkylated compound could be followedconveniently by use of a color test on samples of the reaction mixture;this is illustrated below, using ethylene oxide as the alkylating agent.

120 g. of the mixture of products obtained above in part B, whichcontained a small, undetermined amount of4,4-bis(benzimidazol-Z-yl)stilbene, was mixed with 360 ml. ofZ-methoxyethano-l and 27 g. of a 50% aqueous solution of sodiumhydroxide in a one-liter three-neck flask fitted with a thermometer, gasinlet to the void above the reaction mixture, a U-shaped manometerfilled with one and one-half inches of mercury, and a high-speedagitator. The mixture was heated to 74 C. to dissolve the solid. Thepresence of 4,4-bis(benzimidazol-2-yl) stilbene in the mixture wasdetected qualitatively by the following test: V

A 0.1 ml. sample of the mixture was mixed with 35 ml. of ethanol and toa 1.0 ml. aliquot of the resulting yellow solution there was addeddropwise, from a 1 ml. graduated pipette, 0.01 N nitric acid until theyellow color disappeared (in this instance, 0.15 ml. of the acid wasrequired). The colorless solution was diluted with water to a volume of2.0 ml. There was then added eight drops of a solution of 1.0 g. ofohromic nitrate in 206 ml. of water. The development of a yellow colorin. the solution indicated the presence of 4,4'-bis (benzimidazol-Z-yl)stilb ene.

Ethylene oxide was passed into the reaction vessel while maintaining thereaction mixture at 7480 C. At intervals often-fifteen minutes, 0.1 ml.samples of the reaction mixture were removed and tested as indicatedabove for presence of 4,4'-bis(benzim=idazol2-yl)stilbene. After seventyminutes of passage of ethylene oxide into the reaction vessel, thechromic nitrate solution failed to cause development of a yellow colorin the above test showing that no 4,4'-bis(benzirnidaZol-2-yl)stilbeneremained in the reaction mixture. The total weight of ethylene oxideabsorbed by the reaction mixture was 22.1 g.

The reaction mixture was transferred to a two-liter beaker, cooled to 50C., and 1500 ml. of warm (50 C.) water was added slowly with stirring.Then 400 g. of ice was added to cool the mixture to room temperature andthe yellow solid which had separated from solution was collected on afilter and washed free of alkali with Water. There was thus obtained 118g. of yellow product which consisted chiefly of a mixture ofO-hydroxyethylated and, to a lesser extent, N-hydroxyethylated,derivatives of 4 -(benzimidazol-2-yl)-4'-{l-[2-hydroxy-3- (2,3dihydroxypropoxy)] propylbenzimidazol 2 yl}- stilbene together withsmall amounts of 4-(benzirnidazol-v 2 yl) 4' [1 (2hydroxyethyl)benzimidazol 2- yl] stilbene and 4-(benzimidazol-2-yl)-4'-{1- [2-(2-hydroxyethoxy)ethyl] benzimidazol2-yl}stilbene. Thecomponents of this mixture, although separable by conventionalfractionation procedures, are all whitening and brightening agents and,moreover, the mixture was found to have excellent stability in thepresence of dried white deter- Therefore, for practical purposes, it wasfound to be preferable to'use gents and to whiten these detergents.

the mixture of'the several compounds obtained as de scribed abovewithout purification.

E. When the product of part Dfabove is reacted further with ethyleneoxide, or alternatively when the process of hydroxyethylation of theproduct of par-t B is continued for some time after the4,4-bis(benzimidazol-2- yl)stilbene has disappeared from the mixture asdetermined by the color test described above, there are obtainedhydroxyethylated compounds having progressively increasing solubility inglacial acetic acid; on the other hand, the solubility of these productsin alkaline alcohol solutions decreases due to increasing proportion ofN,N- dialkylated derivatives in the mixture. These acetic acidsolublemixtures are especially useful embodiments of the newbenzimidazolylstilbenes for incorporation into detergents. Thepreparation of a representative mixture of this type is described below.

To a 200 ml. three-neck flask fitted with a magnetic stirrer, gas inlet,a U-shaped manometer filled with one inch of mercury, and a thermometerthere were added 15 g. of4-(benzimidazol-2-yl)-4-[1-(2,3-dihydroxypropyl)benzimidazol 2yllstilbene containing a small amount of4,4-bis(benzimidazol-2-yl)stilbene (prepared in the manner described inpart B above), 3.0 g. of a 50% aqueous solution of sodium hydroxide, and75 ml. of 2-methoxyethanol. The mixture was stirred and heated todissolve all of the solid, and the solution thus obtained was thenmaintained at a temperature of 6570 C. while ethylene oxide was passedinto the reaction vessel above the surface of the mixture. After 9.5 g.of ethylene oxide had been absorbed (requiring about one hour) thereaction mixture was cooled to 50 C., diluted with 250 ml. of warm (50C.) water, cooled to room temperature, and filtered. The solid thuscollected was washed free of alkali with Water, and dried. There wasobtained in this manner 14.5 g. of yellow powder consisting chiefly ofhydroxyethylated derivatives of the 4 (benzimidazol 2 yl) 4' [1 (2,3dihydroxypropyl)-benzimidazol 2-yllstilbene containing 1-4 oxyethyl (OCHCH residues; representative of these is the compound having thestructural formula CHOH CH9O-CH -CHOHCHg(O-CH1CH2)20H This mixturewhitened dried detergent powders and was stable therein and for thisreason was especially adapted to use in white solid detergents. Themixture was only slightly soluble in alkaline 2-methoxyethanol andalkaline ethanol solution; it was soluble in cold glacial acetic acid.

When the benzimidazolylstilbenes described -in the foregoing Examples1-28, inclusive, were dispersed in aqueous media, the products in eachinstance fiuoresced blue-white under ultraviolet light and showed a widerange of absorption in the ultraviolet region. Each of the products ofthese examples was dissolved in a suitable. solvent, for instance,alkaline ethanol, alkaline 2 methoxyethanol, N,N-dimethylformamide, orglacial acetic acid, depending on the solubility characteristics of theparticular product, and the solution thus obtained was poured withvigorous stirring into the desired quantity of an aqueous solution of asoap or of an anionic or colored fabrics.

non-ionic detergent.- The resulting fluorescent dispersions were used todye white and colored natural and synthetic fibers. All 'of thebenzimidazolylstilbene products of the above examples were found to besubstantive even from low concentrations, e.g. 0.0001%, in theseaqueousmedia to white and colored fabrics of cotton,'cellulose acetate, nylon,viscose rayon, Orlon and silk, thereby imparting a blue-white hue to thewhite fabrics and brightening the colored fabrics. Moreover, theseproducts all had relatively high stability to light as determined byaccelerated exposure tests. In the dispersions in soaps and detergentsthe products Were substantially unaffected by a concentration of sodiumhypochlorite of 0.2% by weight. My new products were thus found to beespecially useful as whitening and brightening agents to be used inconjunction with the laundering of white and The methods employed forincorporating all of the above examples of benzimidazolylstilbenes intosoaps and detergents are illustrated hereinbelow. Other methods whichwill be readily apparent to those skilled in the art can be employed ifdesired.

In s0ap.0ne part by weight of the pale yellow solid described above inExample 21 (obtained in a yield of 96 g. by thehydroxyethoxyhydroxypropylattion of 4,4-

bis(benzimidazol-Z-yl)stilbene) was dissolved in a mixture of one partby weight of a 50% aqueous solution of sodium hydroxide and eight partsby volume of ethanol. One part by volume of this solution was oured withstirring into a warm (55 C.) soap bath consisting of four parts byweight of the sodium salts of the O -C fatty acids derived from tallowand 1000 parts by weight of water. Eight parts by volume of theresulting aqueous dispersion was diluted further by mixing with 192parts by volume of water containing 0.76 part by weight of the soapindicated above. The mixture thus obtained was employed in conventionalmanner as a dye bath for treating white fabrics of cotton, nylon,cellulose acetate, silk, and viscose rayon. Each of these white fabricswas beneficially whitened by this procedure. In a'erergent'I (parts areby weight).-The detergent consisted of 21.8% of a mixture of sodiumlauryl sulfate and sodium dodecylbenzenesulfonates, 18.2% of sodiumsulfate, and 60% of sodium triphosphate. To a thin paste of 2000 partsof the detergent and 1500 parts of water there was added at 70 C. asolutionof one part of 4,4-bis(benzimidazol-2-yl)stilbene in 10 parts of2- methoxyethanol and 4 parts of a 33%% aqueous solution of sodiumhydroxide. Two hundred parts of the well-stirred paste was poured into5000 parts of rapidly agitated Water at 60 C. To 80 ml. of thisdispersion there Was added 200 ml. of water and the resulting mixturewas employed as a dye bath in conventional fashion to dye white fabricsof nylon, cotton, cellulose acetate, viscose rayon, Orlon, and silk. Toeach of these white fabrics this procedure imparted a blue-whitefluorescence. V In detergent II.Using the immediately foregoingprocedure, there was substituted for the detergent I a detergentcomposed of 19.1% of sodium dodecylbenzenesulfonates, 15.6% of sodiumsulfate, 55.0% of sodium triphosphate and 10.3% of sodium carbonate. Thewhite'fabrics Were in each case beneficially whitened.

In detergent III (parts are by weight).-A mixture of 20 parts of the14.5 g. of yellow powder obtained in Example 28E above, 100 parts oftert-dodecylmercaptopolye'thoxy'ethanol (Nonic 218), and 40 parts ofglacial acetic acidwas warmed on a water bath to dissolve the solid.Sixteen pants of the solution thus obtained were poured into 20,000parts of water at 55 C.; then 8 parts of the resulting dispersion waspoured into 192 parts of warm (55 C.) water, and the mixture was used towhiten and brighten white and colored fabrics of the type indicatedhereinabove.

The term lorol used in this specification designates the alkyl radicalsof mixed fatty alcohols derived from coconut oil, v

I claim:

where R R R and R are radicals of the class consisting of hydrogen,lower alkyl containing 1-4 carbon atoms, lower alkoxy containing 1-4carbon atoms, and halo, and Y and Y are radicals of the class consistingof hydrogen, lower alkyl containing 1-6 carbon atoms, hydroxy-loweralkyl containing 2-6 carbon atoms, 2-hydroxy-3-sulfopropyl,hydroxy-oxaalkyl containing 3-15 carbon atoms, carboxy-lower alkylcontaining 2-6 carbon atoms, cyano-lower alkyl containing 3-6 carbonatoms, allyl, methallyl, and monocyclic aralkyl containing 7-11 carbonatoms.

2. A detergent composition comprising a water-soluble synthetic organicnon-ionic detergent, and dispersed therein 0.02-0.5% by weight of abenzimidazolylstilbene having the structural formula C Q \N/ l i where Yis a hydroxy-lower alkyl radical containing 2-6 7 carbon atoms and Y isa hydroxy-oxaalkyl radical containing 3-15 carbon atoms.

3. A detergent composition comprising a water-soluble synthetic organicanionic detergent and dispersed therein 0.02-0.5% by weight of abenzimidazolylstilbene having the structural formula H of 3 3 1] where Yis a hydroxy-lower alkyl radical containing 2-6 carbon atoms and Y is ahydroxy-oxaalkyl radical containing 3-15 carbon atoms.

4. A detergent composition comprising a water-soluble synthetic rganicanionic sulfonated: d t g m g p rsed therein 0.02-0.5 by weight of 'abeiizimidazol'ylbenc having the structural formula a EO A I A I CH C YIwhere Y is a hydroxy-lower alkyl radical containing 2-6 carbon atomsand'Y is a hydroxymnaalkyl radical containing 3-15 carbon atoms.

5. A detergent composition comprising a water-soluble soap and dispersedtherein 0.02-0.5% by weight of'a benzimidazolylstil-bene having thestructural formula so N where Y is a hydroxy-lower alkyl radicalcontaining 2-6 carbon atoms and Y is a hydroxy-oxaalkyl radicalcontaining 3-15 carbon atoms.

6. A detergent composition comprising a water-soluble synthetic organicanionic detergent and dispersed therein 0.02-0.5% by weight of abenzimidazolylstilhene having the structural formula wherein Y ishydrogen and Y is a hydroxy-oxaalkyl radical containing 3-15 carbonatoms.

7. A detergentcomposition comprising a water-soluble synthetic organicanionic detergent and dispersed therein 00 0.02-0.5% by weight of abenzimidazolylstilbene having the structural formula CH- 4" v 10 on 15where Y is allyl and Y ishydrogen.

' f 35 36 8. Adam-gent composition comprising a. water-soluble.References Cited in the file of this patent synthetic organic, non-ionicdetergent and dispersed there UNITED STATES PATENTS in ODE-0.5% byweight .of-a bcnzimidazolylstilbcne haw. I H mg the Structural formula 2,335,271, Gl aenacher et. a1, Nov, 30, 1 943 r 5 2,463,264, Graenecheret a l. Mar, 1, 1949 2,488,095!- Graenacher et a1. Nov. 15,1949.2,515,173 Ack e i'man n et' al. July 18, 195.0 CH? 2,668,777 Gold et a1Feb. 9, 1954 2,733,165 Williams et a1. Ian. 31, 1956 10 2,773,869Leavitt Dec. 11, 1956 Yl 2,784,184 Zweieller et, a1. Mar. 5, 1957 N,FOREIGN PATENTS HO 15 877,755 Germany May 26, 1953 OTHER REFERENCESWright: Chem. Review, v01. 48, pp. 456-8, 476-80 where Y i5 allyl and-Y" is h drogen, 1951 ethanol lines 35 and 36, for "4benzimidazol-"- readUNITED STATES PAfENT' OFF ICE CERTIFICATE OF CORRECTION I Patent No.2,937,148 May 17 1960 Nathan N. Crounse It is hereby certified thaterror appears in the printed specification of the above numbered patentrequiring correction and that the said Letters Patent should read ascorrected below.

Column 2- line 12, for "'-3 [(2-" read -3[2(2' column 5, line 67 for"'T- fluoro(benzimidazol" read --fluoro benzimidazolline 69, for"-dibromo(benzimidazclread dibromobenzimidazol same column 5, line 71,for "-tri l chloro(benzimidazol-" read -';-trich1orobenzimidazolcolumnline 4L8 for "'3- '[2-" read -3-[2-(2- column 8,v line 45, for "4, 4"-'read 4,4- column 9, line 13 for dimethylfarmamide" readdimethylformamide line 22-, for "In 250 mlg" read In a 250 ml. column10, line 30, for -"4,4-" read 454 column ll line 49, before "To a"insert B. column 15, line 22, for '"ethanoD read 1 4-(benzimidazolcolumn18, lines 23 and 24, lower portion of the formula should appear as shownbelow instead of as in the patent:

column 22, line 44,; for 50% C'.--" read 50 C. column 26, line 66, for"-3[2" read -3-[2-(2- column 277,; line 49 for -"Oalkylatev readO-alkylated column 29 line 28,; for "'bis(benezimidazol readbis(benzimidazolcolumn 30, line 45, for "oftenfifteen-" readoften-fifteen column 32 line 24 for "hydroxyethoxyhydroxypropylattion"read hydroxyethoxyhydroxypropylation Signed and sealed this 31st day ofJanuary 1961-.

(SEAL) Attest:

KARL H. AXLINE ROBERT C, WATSON Attesting Officer Commissioner ofPatents

1. A DETERGENT COMPOSITION COMPRISING A DETERGENT SELECTED FROM THEGROUP CONSISTING OF WATER-SOLUBLE SOAPS, WATER-SOLUBLE NON-SOAPSYNTHETIC ORGANIC ANIONIC DETERGENTS, AND WATER-SOLUBLE SYNTHETICORGANIC NON-IONIC DETERGENTS, AND DISPERSED THEREIN 0.02-0.5% BY WEIGHTOF A BENZIMIDAZOLYSTIBENE HAVING THE STRUCTURAL FORMULA